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Fencer Vulns
high 7.5

CVE-2025-53629 json

cpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests Vulnerability

published 2025-07-10 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21055

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using Transfer-Encoding: chunked in the header can allocate memory arbitrarily in the server, potentially leading to its exhaustion. This vulnerability is fixed in 0.23.0. NOTE: This vulnerability is related to CVE-2025-53628.

Patch / fix

  • cpp-httplib_project cpp-httplib 0.23.0
  • yhirose cpp-httplib 0.23.0
  • cpp-httplib Debian 13 0.18.7-1+deb13u1
  • cpp-httplib Debian 14 0.25.0+ds-3

debian advisories DEBIAN-CVE-2025-53629

  • cpp-httplib SLES for SAP applications 16.0, SLES 16.0 0.22.0-160000.4.1

suse advisories SUSE-SU-2026:20600-1

  • cpp-httplib openSUSE Leap 16.0 0.22.0-160000.4.1

opensuse advisories openSUSE-SU-2026:20295-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-53629 updated cvss 7.5

cpp-httplib: cpp-httplib Unbounded Memory Allocation

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-qjmq-h3cc-qv6w referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • yhirose cpp-httplib

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.